Studies have been undertaken to correlate the electrophoretic properties of heterogeneous nuclear RNA with other definable characteristics of these molecules such as chain length, conformation, and rates of synthesis. Although grossly similar, it appears that numerous differences exist between the group of RNAs associated with ribosomal structure and hnRNA molecules. These differences appear sufficiently great to result in marked differences in electrophoretic properties. The nature of these differences and the applicability of gel electrophoresis for the study of hnRNA are currently under study. BIBLIOGRAPHIC REFERENCES: Peacock, A.C., Bunting, S.L., and Nishinaga, K.: Conformational states of 18S rRNA from HeLa cells detected by gel electrophoresis. Biochim. Biophys. Acta 475: 352-365, 1977.